The present invention relates to a soil sampling device and, more particularly, to a self contained soil sampling device for obtaining soil samples for soil testing.
Soil sampling devices are used to obtain a sample of soil for analyzing the soil content including, for example, volatile organic compounds (VOCs) which may have permeated the soil. Typically, soil sampling devices include a barrel which includes an open end for inserting into the soil and a plunger which is adapted to extend through the barrel to expel the collected soil sample from the barrel for subsequent testing. Often, the soil sampling devices include a removable cover which is placed over the open end of the barrel after the soil sample has been taken so that the soil sampling device can be transported to a laboratory setting, including for example testing facilities which may be located at the soil sampling site, where the cap is then removed and the soil is expelled from the barrel by the plunger.
For example, in U.S. Pat. No. 5,706,904 to Turriff et al., a reusable soil sampling device is disclosed which includes a barrel and a plunger assembly. The plunger assembly includes a shaft which extends to the end wall of the barrel and a piston mounted to the distal end of the shaft and a pair of outwardly extending arms mounted to the medial portion of the shaft. Initially, the plunger assembly is fully extended into the barrel such that the plunger is generally positioned at the mouth of the barrel. When taking a soil sample, however, the plunger is pulled through the barrel, somewhat like a syringe, during which time the barrel is filled with soil. The Turriff piston includes a pair of seals which engage the inner surface of the barrel to minimize the loss of the VOCs in the soil during the filling of the barrel. Once the barrel is completely filled with the soil sample, the arms of the piston assembly are rotated and seated in a holding structure provided on the end wall of the barrel. In this manner, the piston assembly is in a fixed, fully retracted position in the barrel. In order to expel the soil sample from the barrel, the arms are then rotated back to a release position so that the plunger can then be again extended into the barrel to thereby expel the soil sample from the barrel with the piston. However, it has been found that the piston assembly is hard to manipulate, and that over time, the space between the shaft of the piston and the end wall of the barrel may become clogged with soil and, thus, prevent the piston from properly operating.
In U.S. Pat. No. 5,343,771, another reusable soil sampling device is disclosed which includes a barrel and a piston assembly which is slidably mounted in the barrel through an end wall of the barrel. The piston assembly includes a shaft and a piston on one end of the shaft and a handle on the opposed end of the shaft. The piston assembly is biased in a retracted position in the barrel by a spring which is positioned between the handle and a handle of the barrel. The soil sampling device further includes a cap which is mounted to the open end of the barrel after the soil sample has been taken. Other such arrangements can be found in U.S. Pat. No. 3,326,049 to Eley. In the Eley device, the plunger assembly includes a scale on the shaft of the plunger assembly in order to read the displaced volume of the sample when soil is expelled from the barrel. The Eley sampling device permits several samples to be taken from a single core sample.
In U.S. Pat. No. 5,522,271 to Turriff et al., a soil sampling device is disclosed which includes a barrel and a plug, which is integrally molded with the barrel. The plug is positioned inside the barrel and is spaced from the mouth portion. The plug includes a frangible section which is integrally molded with the barrel. In order to obtain a soil sample, however, the frangible section must be supported by a support member which is inserted into the second open end of the barrel and extended into the barrel to make direct contact with the plug. After a soil sample has been taken, a cap is placed over the open end of the barrel to retain the soil sample therein. In order to expel the soil sample for later testing, the support member is removed from the barrel and a second device (55) is inserted into the barrel to apply a force to the plug to thereby break the frangible section in order to expel the soil sample. Thus, the Turriff'271 soil sampling device requires four components: The barrel; the cap; the support member; and the expulsion device (55). As a result, the Turriff'271 device is relatively complicated to use and ultimately, as a result of the several component parts, is more costly than most conventional sampling devices.
The process of collecting soil samples typically includes collecting at least two samples, one for analyzing the soil content and a second sample for determining the dry weight of the soil being analyzed. Additionally, there are soil sampling guidelines and regulations which require a different sample size depending on the contents of various compounds within the soil. For example, the Environmental Protection Agency (EPA) has set forth regulations regarding the collection of soil or oily waste samples that are to be analyzed for their content of VOCs, which require that either a 25 g sample or a 5 g sample be collected depending on the levels of analytes present at the sampling site. Therefore, if an area to be sampled has no previous analytical history, both samples must be taken, in addition to a dry weight sample, to avoid a second trip to the site to collect the appropriate sample once the level of analytes is known. Even if the level of analytes is known prior to sampling the soil, a second sample is still required for determining the dry weight of the soil. Because the sampling devices proposed and discussed above include only a single barrel and plunger assembly or the like, multiple sampling devices are required when two or more separate samples must be collected. Furthermore, multiple sampling devices or jars are often required even when only a single sample is required for analytical purposes, as it is often necessary to collect a second sample for the dry weight analysis.
Consequently, there is a need for a simple single use soil sampling device which maintains the integrity of the VOCs in the soil sample, and yet provides the ease of sampling and expulsion of the collected soil sample with fewer steps and fewer components than heretofore known. Furthermore, the single use soil sampling device must accommodate multiple soil sample collection procedures by providing a sampling device having two or more chambers, thereby being capable of collecting two or more separate samples.